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1.
Int J Mol Sci ; 22(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066536

RESUMO

Plant food production is severely affected by fungi; to cope with this problem, farmers use synthetic fungicides. However, the need to reduce fungicide application has led to a search for alternatives, such as biostimulants. Rare-earth elements (REEs) are widely used as biostimulants, but their mode of action and their potential as an alternative to synthetic fungicides have not been fully studied. Here, the biostimulant effect of gadolinium (Gd) is explored using the plant-pathosystem Arabidopsis thaliana-Botrytis cinerea. We determine that Gd induces local, systemic, and long-lasting plant defense responses to B. cinerea, without affecting fungal development. The physiological changes induced by Gd have been related to its structural resemblance to calcium. However, our results show that the calcium-induced defense response is not sufficient to protect plants against B. cinerea, compared to Gd. Furthermore, a genome-wide transcriptomic analysis shows that Gd induces plant defenses and modifies early and late defense responses. However, the resistance to B. cinerea is dependent on JA/ET-induced responses. These data support the conclusion that Gd can be used as a biocontrol agent for B. cinerea. These results are a valuable tool to uncover the molecular mechanisms induced by REEs.


Assuntos
Arabidopsis/imunologia , Arabidopsis/microbiologia , Botrytis/fisiologia , Ciclopentanos/metabolismo , Etilenos/metabolismo , Gadolínio/farmacologia , Oxilipinas/metabolismo , Substâncias Protetoras/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Ácido Salicílico/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Ativação Transcricional/efeitos dos fármacos , Ativação Transcricional/genética
2.
Ecotoxicol Environ Saf ; 220: 112406, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119927

RESUMO

Boron (B) excess gives rise to a serious agricultural problem. In this study, we identified a B toxicity responsive transcription factor AtWRKY47 in Arabidopsis thaliana. The T-DNA insertion mutants Atwrky47 showed enhanced tolerance to B toxicity with better growth parameters under high B conditions compared to wild-type Col-0 plants. Quantitative analysis of AtWRKY47 mRNA abundance indicated that it was down-regulated under B toxicity conditions. Fluorescently labeled AtWRKY47 protein was localized in nucleus. In contrast to the phenotype of Atwrky47 mutants, overexpression of AtWRKY47 in Col-0 background resulted in lower biomass, less chlorophyll content, and increased sensitivity to B toxicity. More importantly, the B concentration in shoots was higher in the overexpression lines and lower in the Atwrky47 mutants than in Col-0 plants, respectively. These results demonstrate that AtWRKY47 gene plays a key role in regulating plant tolerance to B toxicity.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Boro/metabolismo , Tolerância a Medicamentos , Fatores de Transcrição/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Boro/toxicidade , Tolerância a Medicamentos/genética , Regulação da Expressão Gênica de Plantas , Mutação , Fenótipo , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Fatores de Transcrição/genética
3.
Int J Mol Sci ; 22(9)2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-34063046

RESUMO

Receptor-like kinases (RLKs) constitute a large group of cell surface receptors that play crucial roles in multiple biological processes. However, the function of most RLKs in plants has not been extensively explored, and much less for the class of cell wall associated kinases (WAKs) and WAK-like kinases (WAKLs). In this study, analyses of developmental expression patterns uncovered a putative role of AtWAKL10 in modulating leaf senescence, which was further investigated at physiological and molecular levels. The expression level of AtWAKL10 increased with the developmental progression and was rapidly upregulated in senescing leaf tissues. The promoter of AtWAKL10 contains various defense and hormone responsive elements, and its expression could be significantly induced by exogenous ABA, JA and SA. Moreover, the loss-of-function atwakl10 mutant showed earlier senescence along the course of natural development and accelerated leaf senescence under darkness and hormonal stresses, while plants overexpressing AtWAKL10 showed an opposite trend. Additionally, some defense and senescence related WRKY transcription factors could bind to the promoter of AtWAKL10. In addition, deletion and overexpression of AtWAKL10 caused several specific transcriptional alterations, including genes involved in cell extension, cell wall modification, defense response and senescence related WRKYs, which may be implicated in regulatory mechanisms adopted by AtWAKL10 in controlling leaf senescence. Taken together, these results revealed that AtWAKL10 negatively regulated leaf senescence.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Parede Celular/enzimologia , Folhas de Planta/crescimento & desenvolvimento , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Superfície Celular/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Parede Celular/efeitos dos fármacos , Escuridão , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Mutação/genética , Reguladores de Crescimento de Plantas/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Regiões Promotoras Genéticas , Ligação Proteica/efeitos dos fármacos , Domínios Proteicos , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Frações Subcelulares/metabolismo , Transcrição Genética/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética
4.
Nat Commun ; 12(1): 3941, 2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34168134

RESUMO

In plants, inactivation of either of the thylakoid proteins PGR5 and PGRL1 impairs cyclic electron flow (CEF) around photosystem I. Because PGR5 is unstable in the absence of the redox-active PGRL1, but not vice versa, PGRL1 is thought to be essential for CEF. However, we show here that inactivation of PGRL2, a distant homolog of PGRL1, relieves the need for PGRL1 itself. Conversely, high levels of PGRL2 destabilize PGR5 even when PGRL1 is present. In the absence of both PGRL1 and PGRL2, PGR5 alters thylakoid electron flow and impairs plant growth. Consequently, PGR5 can operate in CEF on its own, and is the target of the CEF inhibitor antimycin A, but its activity must be modulated by PGRL1. We conclude that PGRL1 channels PGR5 activity, and that PGRL2 triggers the degradation of PGR5 when the latter cannot productively interact with PGRL1.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Membrana/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Antimicina A/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Fluorescência Verde/genética , Luz , Proteínas de Membrana/genética , Mutação , Fotossíntese , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Plantas Geneticamente Modificadas , Estabilidade Proteica
5.
Plant Cell Rep ; 40(7): 1101-1114, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34100122

RESUMO

KEY MESSAGE: PePIP2;7, a leaf-specific aquaporin gene in bamboo, is upregulated under abiotic stresses. Overexpressing PePIP2;7 confers abiotic stresses tolerance in transgenic Arabidopsis plant and yeast. Aquaporins (AQPs) participate in the regulation of water balance in plants. However, the function of AQPs in bamboo remains unclear. Here, PePIP2;7 was identified as a leaf-specific aquaporin gene in moso bamboo based on the expression analysis of transcriptome data and PCR. In situ hybridization further indicated that PePIP2;7 was mainly expressed in mesophyll cells of mature leaves, while in immature leaves it was dominant in blade edge cells followed by mesophyll cells. Interestingly, PePIP2;7 was strongly expressed in the mesophyll cells near bulliform cells of immature leaves, suggesting that PePIP2;7 might function in water transport and contribute to leaf unfolding. The transient expression assay showed that PePIP2;7 was a plasma membrane intrinsic protein. Furthermore, PePIP2;7 was upregulated under abiotic stresses such as high light, drought, and NaCl. Compared with Col-0, transgenic Arabidopsis plants overexpressing PePIP2;7 had better seed germination rate, longer taproot length, higher SOD activity, and lower MDA content under abiotic stresses. Besides, yeasts expressing PePIP2;7 also had higher tolerance to stress compared to the control. Taken together, our results show that PePIP2;7 is leaf-specific and involved in stress response, which provides new insights into aquaporin function in bamboo.


Assuntos
Aquaporinas/genética , Folhas de Planta/genética , Proteínas de Plantas/genética , Sasa/genética , Estresse Fisiológico/genética , Antioxidantes/metabolismo , Aquaporinas/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Clorofila/genética , Clorofila/metabolismo , Enzimas/metabolismo , Fluorescência , Regulação da Expressão Gênica de Plantas , Germinação/efeitos dos fármacos , Manitol/farmacologia , Filogenia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Reação em Cadeia da Polimerase em Tempo Real , Salinidade , Cloreto de Sódio/farmacologia , Estresse Fisiológico/fisiologia
6.
Plant Cell Rep ; 40(7): 1127-1139, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33973072

RESUMO

KEY MESSAGE: MdBZR1 directly binds to the promoter of MdABI5 and suppresses its expression to mediate ABA response. The plant hormones brassinosteroids (BRs) and abscisic acid (ABA) antagonistically regulate various aspects of plant growth and development. However, the association between BR and ABA signaling is less clear. Here, we identified MdBZR1 in apple (Malus domestica) and demonstrated that it was activated by BRs and could respond to ABA treatment. Overexpression of MdBZR1 in apple calli and Arabidopsis reduced ABA-hypersensitive phenotypes, suggesting that MdBZR1 negatively regulates ABA signaling. Subsequently, we found that MdBZR1 directly bound to the promoter region of MdABI5 and suppressed its expression. MdABI5 was significantly induced by ABA treatment. And overexpression of MdABI5 in apple calli increased sensitivity to ABA. Ectopic expression of MdABI5 in Arabidopsis inhibited seed germination and seedling growth. In addition, overexpression of MdBZR1 partially attenuated MdABI5-mediated ABA sensitivity. Taken together, our data indicate that MdBZR1 directly binds to the promoter of MdABI5 and suppresses its expression to antagonistically mediate ABA response. Our work contributes to the functional studies of BZR1 and further broadens the insight into the between BR and ABA signaling.


Assuntos
Ácido Abscísico/metabolismo , Malus/genética , Proteínas de Plantas/genética , Ácido Abscísico/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Malus/efeitos dos fármacos , Malus/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Estresse Salino/genética
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 259: 119891, 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-33984715

RESUMO

As primary industrial raw material, the widespread usage of bisphenol A (BPA) has resulted in sustained release and accumulation in the environment. Besides its endocrine-disrupting character, BPA was reported to generate excessive reactive oxygen species (ROS). However, the potential toxic mechanisms of the BPA-induced oxidative damage to plants were poorly understood. In this study, glutathione peroxidase 6 from Arabidopsis thaliana (AtGPX6) was regarded as biomarker to investigate the toxic effects of BPA on plants by multi-spectroscopic techniques and molecular docking method. Firstly, BPA effectively quenched the intrinsic fluorescence of AtGPX6 via static quenching mechanism, and a single binding site of AtGPX6 towards BPA was presumed. Moreover, the binding force was mainly driven by van der Waals forces and hydrogen bonding based on the negative values of ΔH0 and ΔS0, which was consistent with the molecular docking result. In addition, the conformational changes of AtGPX6 accompanied with the enhancement of the hydrophilicity around the tryptophan residues upon the combination with BPA, were evaluated through the combination of the fluorescence, UV-visible absorption and Circular dichroism (CD) spectroscopy. Finally, the inhibitory impact on the development of Arabidopsis seedling roots was observed under BPA exposure. Therefore, the exploration of the molecular mechanism of AtGPX6 with BPA would provide valuable assessments on the toxic effects of BPA on plants.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Compostos Benzidrílicos/toxicidade , Fenóis/toxicidade , Arabidopsis/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Simulação de Acoplamento Molecular
8.
Nat Commun ; 12(1): 2181, 2021 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-33846350

RESUMO

Regulation of stomatal movement is critical for plant adaptation to environmental stresses. The microtubule cytoskeleton undergoes disassembly, which is critical for stomatal closure in response to abscisic acid (ABA). However, the mechanism underlying this regulation largely remains unclear. Here we show that a ubiquitin-26S proteasome (UPS)-dependent pathway mediates microtubule disassembly and is required for ABA-induced stomatal closure. Moreover, we identify and characterize the ubiquitin E3 ligase MREL57 (MICROTUBULE-RELATED E3 LIGASE57) and the microtubule-stabilizing protein WDL7 (WAVE-DAMPENED2-LIKE7) in Arabidopsis and show that the MREL57-WDL7 module regulates microtubule disassembly to mediate stomatal closure in response to drought stress and ABA treatment. MREL57 interacts with, ubiquitinates and degrades WDL7, and this effect is clearly enhanced by ABA. ABA-induced stomatal closure and microtubule disassembly are significantly suppressed in mrel57 mutants, and these phenotypes can be restored when WDL7 expression is decreased. Our results unravel UPS-dependent mechanisms and the role of an MREL57-WDL7 module in microtubule disassembly and stomatal closure in response to drought stress and ABA.


Assuntos
Ácido Abscísico/farmacologia , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Microtúbulos/metabolismo , Estômatos de Plantas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Fluorescência Verde/metabolismo , Microtúbulos/efeitos dos fármacos , Modelos Biológicos , Mutação/genética , Estômatos de Plantas/citologia , Estômatos de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas , Ligação Proteica/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/metabolismo , Ubiquitina/metabolismo , Ubiquitinação/efeitos dos fármacos
9.
Plant Cell ; 33(2): 322-337, 2021 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-33793786

RESUMO

Ethylene is an important phytohormone with pleotropic roles in plant growth, development, and stress responses. ETHYLENE INSENSITIVE2 (EIN2) mediates the transduction of the ethylene signal from the endoplasmic reticulum membrane to the nucleus, where its C-terminus (EIN2-C) regulates histone acetylation to mediate transcriptional regulation by EIN3. However, no direct interaction between EIN2-C and EIN3 has been detected. To determine how EIN2-C and EIN3 act together, we followed a synthetic approach and engineered a chimeric EIN2-C with EIN3 DNA-binding activity but lacking its transactivation activity (EIN2C-EIN3DB). The overexpression of EIN2C-EIN3DB in either wild-type or in the ethylene-insensitive mutant ein3-1 eil1-1 led to a partial constitutive ethylene response. Chromatin immunoprecipitation sequencing showed that EIN2C-EIN3DB has DNA-binding activity, indicating that EIN3DB is functional in EIN2C-EIN3DB. Furthermore, native EIN3 protein levels determine EIN2C-EIN3DB binding activity and binding targets in a positive feedback loop by interacting with EIN2C-EIN3DB to form a heterodimer. Additionally, although EIN3 does not direct affect histone acetylation levels in the absence of EIN2, it is required for the ethylene-induced elevation of H3K14Ac and H3K23Ac in the presence of EIN2. Together, we reveal efficient and specific DNA-binding by dimerized EIN3 in the presence of ethylene to mediate positive feedback regulation, which is required for EIN2-directed elevation of histone acetylation to integrate into an EIN3-dependent transcriptional activation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Ligação a DNA/metabolismo , Etilenos/farmacologia , Retroalimentação Fisiológica , Histonas/metabolismo , Receptores de Superfície Celular/metabolismo , Fatores de Transcrição/metabolismo , Acetilação/efeitos dos fármacos , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/química , Sequência de Bases , DNA de Plantas/metabolismo , Proteínas de Ligação a DNA/química , Domínios Proteicos , Multimerização Proteica/efeitos dos fármacos , Receptores de Superfície Celular/química , Fatores de Transcrição/química
10.
Int J Mol Sci ; 22(7)2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33804990

RESUMO

Herbicide resistance is broadly recognized as the adaptive evolution of weed populations to the intense selection pressure imposed by the herbicide applications. Here, we tested whether transcriptional gene silencing (TGS) and RNA-directed DNA Methylation (RdDM) pathways modulate resistance to commonly applied herbicides. Using Arabidopsis thaliana wild-type plants exposed to sublethal doses of glyphosate, imazethapyr, and 2,4-D, we found a partial loss of TGS and increased susceptibility to herbicides in six out of 11 tested TGS/RdDM mutants. Mutation in REPRESSOR OF SILENCING 1 (ROS1), that plays an important role in DNA demethylation, leading to strongly increased susceptibility to all applied herbicides, and imazethapyr in particular. Transcriptomic analysis of the imazethapyr-treated wild type and ros1 plants revealed a relation of the herbicide upregulated genes to chemical stimulus, secondary metabolism, stress condition, flavonoid biosynthesis, and epigenetic processes. Hypersensitivity to imazethapyr of the flavonoid biosynthesis component TRANSPARENT TESTA 4 (TT4) mutant plants strongly suggests that ROS1-dependent accumulation of flavonoids is an important mechanism for herbicide stress response in A. thaliana. In summary, our study shows that herbicide treatment affects transcriptional gene silencing pathways and that misregulation of these pathways makes Arabidopsis plants more sensitive to herbicide treatment.


Assuntos
Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Herbicidas/farmacologia , Ácido 2,4-Diclorofenoxiacético/farmacologia , Aciltransferases/genética , Proteínas de Arabidopsis/genética , Cromatina/química , Cromatografia Líquida de Alta Pressão , Desmetilação do DNA , Metilação de DNA , Mutação , Ácidos Nicotínicos/farmacologia , Proteínas Nucleares/genética , RNA de Plantas/genética , RNA-Seq , Transcrição Genética
11.
J Plant Physiol ; 261: 153415, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33894579

RESUMO

Ammonium (NH4+) inhibits primary root (PR) growth in most plant species when present even at moderate concentrations. Previous studies have shown that transport of indole-3-acetic acid (IAA) is critical to maintaining root elongation under high-NH4+ stress. However, the precise regulation of IAA homeostasis under high-NH4+ stress (HAS) remains unclear. In this study, qRT-PCR, RNA-seq, free IAA and IAA conjugate and PR elongation measurements were conducted in genetic mutants to investigate the role of IAA biosynthesis and conjugation under HAS. Our data clearly show that HAS decreases free IAA in roots by increasing IAA inactivation but does not decrease IAA biosynthesis, and that the IAA-conjugating genes GH3.1, GH3.2, GH3.3, GH3.4, and GH3.6 function as the key genes in regulating high-NH4+ sensitivity in the roots. Furthermore, the analysis of promoter::GUS staining in situ and genetic mutants reveals that HAS promotes IAA conjugation in the elongation zone (EZ), which may be responsible for the PR inhibition observed under HAS. This study provides potential new insight into the role of auxin in the improvement of tolerance to NH4+.


Assuntos
Compostos de Amônio/metabolismo , Arabidopsis/crescimento & desenvolvimento , Ácidos Indolacéticos/farmacologia , Raízes de Plantas/crescimento & desenvolvimento , Compostos de Amônio/administração & dosagem , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Homeostase/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Estresse Fisiológico
12.
Int J Mol Sci ; 22(8)2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33920993

RESUMO

Polyamines (PAs) dramatically affect root architecture and development, mainly by unknown mechanisms; however, accumulating evidence points to hormone signaling and reactive oxygen species (ROS) as candidate mechanisms. To test this hypothesis, PA levels were modified by progressively reducing ADC1/2 activity and Put levels, and then changes in root meristematic zone (MZ) size, ROS, and auxin and cytokinin (CK) signaling were investigated. Decreasing putrescine resulted in an interesting inverted-U-trend in primary root growth and a similar trend in MZ size, and differential changes in putrescine (Put), spermidine (Spd), and combined spermine (Spm) plus thermospermine (Tspm) levels. At low Put concentrations, ROS accumulation increased coincidently with decreasing MZ size, and treatment with ROS scavenger KI partially rescued this phenotype. Analysis of double AtrbohD/F loss-of-function mutants indicated that NADPH oxidases were not involved in H2O2 accumulation and that elevated ROS levels were due to changes in PA back-conversion, terminal catabolism, PA ROS scavenging, or another pathway. Decreasing Put resulted in a non-linear trend in auxin signaling, whereas CK signaling decreased, re-balancing auxin and CK signaling. Different levels of Put modulated the expression of PIN1 and PIN2 auxin transporters, indicating changes to auxin distribution. These data strongly suggest that PAs modulate MZ size through both hormone signaling and ROS accumulation in Arabidopsis.


Assuntos
Arabidopsis/anatomia & histologia , Citocininas/metabolismo , Ácidos Indolacéticos/metabolismo , Meristema/anatomia & histologia , Putrescina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arginina/farmacologia , Peróxido de Hidrogênio/metabolismo , Meristema/efeitos dos fármacos , Modelos Biológicos , Mutação/genética , NADPH Oxidases/metabolismo , Tamanho do Órgão/efeitos dos fármacos , Fenótipo , Iodeto de Potássio/farmacologia , Transdução de Sinais/efeitos dos fármacos
13.
Int J Mol Sci ; 22(8)2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33924609

RESUMO

Osmotic stress severely inhibits plant growth and development, causing huge loss of crop quality and quantity worldwide. Melatonin is an important signaling molecule that generally confers plant increased tolerance to various environmental stresses, however, whether and how melatonin participates in plant osmotic stress response remain elusive. Here, we report that melatonin enhances plant osmotic stress tolerance through increasing ROS-scavenging ability, and melatonin receptor CAND2 plays a key role in melatonin-mediated plant response to osmotic stress. Upon osmotic stress treatment, the expression of melatonin biosynthetic genes including SNAT1, COMT1, and ASMT1 and the accumulation of melatonin are increased in the wild-type plants. The snat1 mutant is defective in osmotic stress-induced melatonin accumulation and thus sensitive to osmotic stress, while exogenous melatonin enhances the tolerance of the wild-type plant and rescues the sensitivity of the snat1 mutant to osmotic stress by upregulating the expression and activity of catalase and superoxide dismutase to repress H2O2 accumulation. Further study showed that the melatonin receptor mutant cand2 exhibits reduced osmotic stress tolerance with increased ROS accumulation, but exogenous melatonin cannot revert its osmotic stress phenotype. Together, our study reveals that CADN2 functions necessarily in melatonin-conferred osmotic stress tolerance by activating ROS-scavenging ability in Arabidopsis.


Assuntos
Adaptação Fisiológica , Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Melatonina/farmacologia , Pressão Osmótica , Receptores Acoplados a Proteínas G/metabolismo , Estresse Fisiológico , Adaptação Fisiológica/efeitos dos fármacos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Catalase/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Mutação/genética , Espécies Reativas de Oxigênio/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética
14.
Int J Mol Sci ; 22(7)2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33805388

RESUMO

FCS-like zinc finger family proteins (FLZs), a class of plant-specific scaffold of SnRK1 complex, are involved in the regulation of various aspects of plant growth and stress responses. Most information of FLZ family genes was obtained from the studies in Arabidopsis thaliana, whereas little is known about the potential functions of FLZs in crop plants. In this study, 37 maize FLZ (ZmFLZ) genes were identified to be asymmetrically distributed on 10 chromosomes and can be divided into three subfamilies. Protein interaction and subcellular localization assays demonstrated that eight typical ZmFLZs interacted and partially co-localized with ZmKIN10, the catalytic α-subunit of the SnRK1 complex in maize leaf mesophyll cells. Expression profile analysis revealed that several ZmFLZs were differentially expressed across various tissues and actively responded to diverse abiotic stresses. In addition, ectopic overexpression of ZmFLZ25 in Arabidopsis conferred hypersensitivity to exogenous abscisic acid (ABA) and triggered higher expression of ABA-induced genes, pointing to the positive regulatory role of ZmFLZ25 in plant ABA signaling, a scenario further evidenced by the interactions between ZmFLZ25 and ABA receptors. In summary, these data provide the most comprehensive information on FLZ family genes in maize, and shed light on the biological function of ZmFLZ25 in plant ABA signaling.


Assuntos
Ácido Abscísico/metabolismo , Proteínas de Plantas/genética , Zea mays/genética , Ácido Abscísico/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Estudo de Associação Genômica Ampla , Família Multigênica , Especificidade de Órgãos , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estresse Fisiológico/genética , Zea mays/efeitos dos fármacos , Dedos de Zinco/genética
15.
Int J Mol Sci ; 22(9)2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33925054

RESUMO

A non-destructive thermal imaging method was used to study the stomatal response of salt-treated Arabidopsis thaliana plants to excessive light. The plants were exposed to different levels of salt concentrations (0, 75, 150, and 220 mM NaCl). Time-dependent thermograms showed the changes in the temperature distribution over the lamina and provided new insights into the acute light-induced temporary response of Arabidopsis under short-term salinity. The initial response of plants, which was associated with stomatal aperture, revealed an exponential growth in temperature kinetics. Using a single-exponential function, we estimated the time constants of thermal courses of plants exposed to acute high light. The saline-induced impairment in stomatal movement caused the reduced stomatal conductance and transpiration rate. Limited transpiration of NaCl-treated plants resulted in an increased rosette temperature and decreased thermal time constants as compared to the controls. The net CO2 assimilation rate decreased for plants exposed to 220 mM NaCl; in the case of 75 mM NaCl treatment, an increase was observed. A significant decline in the maximal quantum yield of photosystem II under excessive light was noticeable for the control and NaCl-treated plants. This study provides evidence that thermal imaging as a highly sensitive technique may be useful for analyzing the stomatal aperture and movement under dynamic environmental conditions.


Assuntos
Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Termografia/métodos , Arabidopsis/efeitos dos fármacos , Cinética , Luz , Pressão Osmótica , Complexo de Proteína do Fotossistema II/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Complexo de Proteína do Fotossistema II/efeitos da radiação , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/fisiologia , Estômatos de Plantas/efeitos da radiação , Transpiração Vegetal/efeitos dos fármacos , Transpiração Vegetal/fisiologia , Transpiração Vegetal/efeitos da radiação , Salinidade , Cloreto de Sódio/administração & dosagem , Estresse Fisiológico
16.
Int J Mol Sci ; 22(6)2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33805821

RESUMO

Drought is the most serious abiotic stress, which significantly reduces crop productivity. The phytohormone ABA plays a pivotal role in regulating stomatal closing upon drought stress. Here, we characterized the physiological function of AtBBD1, which has bifunctional nuclease activity, on drought stress. We found that AtBBD1 localized to the nucleus and cytoplasm, and was expressed strongly in trichomes and stomatal guard cells of leaves, based on promoter:GUS constructs. Expression analyses revealed that AtBBD1 and AtBBD2 are induced early and strongly by ABA and drought, and that AtBBD1 is also strongly responsive to JA. We then compared phenotypes of two AtBBD1-overexpression lines (AtBBD1-OX), single knockout atbbd1, and double knockout atbbd1/atbbd2 plants under drought conditions. We did not observe any phenotypic difference among them under normal growth conditions, while OX lines had greatly enhanced drought tolerance, lower transpirational water loss, and higher proline content than the WT and KOs. Moreover, by measuring seed germination rate and the stomatal aperture after ABA treatment, we found that AtBBD1-OX and atbbd1 plants showed significantly higher and lower ABA-sensitivity, respectively, than the WT. RNA sequencing analysis of AtBBD1-OX and atbbd1 plants under PEG-induced drought stress showed that overexpression of AtBBD1 enhances the expression of key regulatory genes in the ABA-mediated drought signaling cascade, particularly by inducing genes related to ABA biosynthesis, downstream transcription factors, and other regulatory proteins, conferring AtBBD1-OXs with drought tolerance. Taken together, we suggest that AtBBD1 functions as a novel positive regulator of drought responses by enhancing the expression of ABA- and drought stress-responsive genes as well as by increasing proline content.


Assuntos
Ácido Abscísico/metabolismo , Adaptação Fisiológica/genética , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Endonucleases/genética , Regulação da Expressão Gênica de Plantas , Ácido Abscísico/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/enzimologia , Proteínas de Arabidopsis/agonistas , Proteínas de Arabidopsis/antagonistas & inibidores , Proteínas de Arabidopsis/metabolismo , Núcleo Celular/metabolismo , Ciclopentanos/metabolismo , Ciclopentanos/farmacologia , Citoplasma/metabolismo , Secas , Endonucleases/antagonistas & inibidores , Endonucleases/metabolismo , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Oxilipinas/metabolismo , Oxilipinas/farmacologia , Células Vegetais/efeitos dos fármacos , Células Vegetais/enzimologia , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/genética , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/enzimologia , Estômatos de Plantas/genética , Plantas Geneticamente Modificadas , Prolina/metabolismo , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Água/metabolismo
17.
Int J Mol Sci ; 22(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806406

RESUMO

The NAC (NAM, ATAF1/2, and CUC2) transcription factors comprise one of the largest transcription factor families in plants and play important roles in stress responses. However, little is known about the functions of potato NAC family members. Here we report the cloning of a potato NAC transcription factor gene StNAC053, which was significantly upregulated after salt, drought, and abscisic acid treatments. Furthermore, the StNAC053-GFP fusion protein was found to be located in the nucleus and had a C-terminal transactivation domain, implying that StNAC053 may function as a transcriptional activator in potato. Notably, Arabidopsis plants overexpressing StNAC053 displayed lower seed germination rates compared to wild-type under exogenous ABA treatment. In addition, the StNAC053 overexpression Arabidopsis lines displayed significantly increased tolerance to salt and drought stress treatments. Moreover, the StNAC053-OE lines were found to have higher activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) under multiple stress treatments. Interestingly, the expression levels of several stress-related genes including COR15A,DREB1A, ERD11, RAB18, ERF5, and KAT2, were significantly upregulated in these StNAC053-overexpressing lines. Taken together, overexpression of the stress-inducible StNAC053 gene could enhance the tolerances to both salt and drought stress treatments in Arabidopsis, likely by upregulating stress-related genes.


Assuntos
Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Solanum tuberosum/genética , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Ácido Abscísico/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Catalase/genética , Núcleo Celular/genética , Secas , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Peroxidase/genética , Plantas Geneticamente Modificadas/efeitos dos fármacos , Cloreto de Sódio/administração & dosagem , Cloreto de Sódio/farmacologia , Solanum tuberosum/efeitos dos fármacos , Superóxido Dismutase/genética , Regulação para Cima/genética
18.
Biomolecules ; 11(2)2021 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672873

RESUMO

Polysaccharides from marine algae are one novel source of plant defense elicitors for alternative and eco-friendly plant protection against phytopathogens. The effect of exopolysaccharides (EPS) produced by Porphyridium sordidum on elicitation of Arabidopsis thaliana defense responses against Fusarium oxysporum was evaluated. Firstly, in order to enhance EPS production, a Box-Behnken experimental design was carried out to optimize NaCl, NaNO3 and MgSO4 concentrations in the culture medium of microalgae. A maximum EPS production (2.45 g/L) higher than that of the control (0.7 g/L) was observed for 41.62 g/L NaCl, 0.63 g/L NaNO3 and 7.2 g/L MgSO4 concentrations. Structurally, the EPS contained mainly galactose, xylose and glucose. Secondly, the elicitor effect of EPS was evaluated by investigating the plant defense-related signaling pathways that include activation of Salicylic or Jasmonic Acid-dependent pathway genes. A solution of 2 mg/mL of EPS has led to the control of fungal growth by the plant. Results showed that EPS foliar application induced phenylalaline ammonia lyase and H2O2 accumulation. Expression profile analysis of the defense-related genes using qRT-PCR revealed the up-regulation of Superoxide dismutases (SOD), Peroxidase (POD), Pathogenesis-related protein 1 (PR-1) and Cytochrome P450 monooxyge-nase (CYP), while Catalase (CAT) and Plant defensin 1.2 (PDF1.2) were not induced. Results suggest that EPS may induce the elicitation of A. thaliana's defense response against F. oxysporum, activating the Salicylic Acid pathway.


Assuntos
Arabidopsis/efeitos dos fármacos , Fusarium/imunologia , Polissacarídeos/biossíntese , Porphyridium/metabolismo , Arabidopsis/imunologia , Arabidopsis/microbiologia , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia por Troca Iônica/métodos , DNA Ribossômico/genética , Interações Hospedeiro-Patógeno , Peróxido de Hidrogênio/metabolismo , Polissacarídeos/farmacologia , Porphyridium/classificação , Porphyridium/genética , RNA Ribossômico 18S/genética
19.
Methods Mol Biol ; 2297: 49-60, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33656669

RESUMO

Seedlings grown in darkness exhibit distinct morphologies comparing with light-grown seedlings. Elongated hypocotyls, closed yellow cotyledons, and the formation of apical hooks are typical characteristics for etiolated seedlings, which are collectively named skotomorphogenesis. Various plant hormones and environmental factors are essential for maintaining skotomorphogenesis. Due to the diverse morphological outcomes in etiolated seedlings grown under different treatments, studies on skotomorphogenesis are of particular importance to reveal the molecular mechanisms underlying plant response to environmental cues. Here, we detailed experimental procedures to facilitate researchers who are investigating etiolation growth-related studies.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Estiolamento/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Cotilédone/efeitos dos fármacos , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Hipocótilo/efeitos dos fármacos , Hipocótilo/genética , Hipocótilo/crescimento & desenvolvimento , Temperatura
20.
Int J Mol Sci ; 22(5)2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33673599

RESUMO

Saline-alkali soil has become an important environmental problem for crop productivity. One of the most effective approaches is to cultivate new stress-tolerant plants through genetic engineering. Through RNA-seq analysis and RT-PCR validation, a novel bZIP transcription factor ChbZIP1, which is significantly upregulated at alkali conditions, was obtained from alkaliphilic microalgae Chlorella sp. BLD. Overexpression of ChbZIP1 in Saccharomyces cerevisiae and Arabidopsis increased their alkali resistance, indicating ChbZIP1 may play important roles in alkali stress response. Through subcellular localization and transcriptional activation activity analyses, we found that ChbZIP1 is a nuclear-localized bZIP TF with transactivation activity to bind with the motif of G-box 2 (TGACGT). Functional analysis found that genes such as GPX1, DOX1, CAT2, and EMB, which contained G-box 2 and were associated with oxidative stress, were significantly upregulated in Arabidopsis with ChbZIP1 overexpression. The antioxidant ability was also enhanced in transgenic Arabidopsis. These results indicate that ChbZIP1 might mediate plant adaptation to alkali stress through the active oxygen detoxification pathway. Thus, ChbZIP1 may contribute to genetically improving plants' tolerance to alkali stress.


Assuntos
Álcalis/toxicidade , Arabidopsis/fisiologia , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Chlorella/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico , Adaptação Fisiológica/genética , Arabidopsis/efeitos dos fármacos , Fatores de Transcrição de Zíper de Leucina Básica/genética , Chlorella/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Tolerantes a Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/fisiologia
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